Flow-bypassing structure of grinding tool and grinding tool having the same

ABSTRACT

A flow-bypassing structure and a grinding tool having the same are provided. A main body of the grinding tool has an intake passage and an exhaust passage. A cylinder is disposed in an interior of the main body and has an air inlet communicated with the intake passage and an air outlet communicated with the exhaust passage to form an airflow pathway. A rotor is disposed in the cylinder, and a rotational axle base is rotatably disposed though the cylinder and in a rotational cooperative relationship with the rotor. An end of the rotational axle base is extended and formed with a rotational working portion outside the cylinder. The surroundings of the rotational working portion define a space. A flow-bypassing passage is communicated with the airflow pathway and the space, and an end of the flow-bypassing passage is open toward the space.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is a CIP of application Ser. No. 14/043,153, filedOct. 1, 2013, the entire contents of which are hereby incorporated byreference.

2. Description of the Prior Art

As disclosed in the prior arts of grinding tools such as TW440488,TWM261316, TWM288839, TWI260255 and TWM349818, the conventional grindingtools have a cylinder disposed in a main body. The cylinder has a rotorwhich is in a rotational cooperative relationship with a rotationalaxle, and a grinding sheet is disposed at an end of the rotational axle.When a high pressure gas enters the cylinder and drives the rotor torotate, the rotational axle and the grinding sheet will be driven togrind an object.

During the grinding operation, the grinding tools rotate in an extremelyhigh speed; therefore, the rotational axle and an axle bearing willgenerate a large amount of heat, and their temperature will risecontinuously due to high-speed rotation. However, the conventionalgrinding tools are not equipped with cooling apparatuses or systems tolower the temperature, so each member has higher temperature, andmembers like the rotational axle and the axle bearing are prone toproblems such as mechanical fatigue, damage, breakdown or the like.Besides, during the process of grinding an object, the grinded part ofthe surface of the object will become a large amount of tiny particles.The particles are prone to remain on the surface of each member and getstuck in the tiny gaps among the members (for example, the gap betweenthe rotational axle and the axle bearing); hence, the grinding tools areprone to have problems like unsmooth rotation or apparatus abrasion, andthe temperature during the operation will rise more easily.

US 20100071926 discloes a pneumatic power tool with air cooling system.The pneumatic air tool includes a housing with a forward angle gearingarranged in a gearing chamber, a motor chamber, a rear air outletsection and a forward air outlet section. The motor chamber includes apneumatic motor with air communication openings, which communicate withboth the rear air outlet section, and the forward air outlet section. Apart of the outlet air is ducted through the forward air outlet sectionincluding a circular groove in the housing which forms part of a coolingchamber. The walls of the groove form together an enlarged heattransferring surface by which the heat generated in the angle gearing isefficiently transferred to the cold exhaust air from the motor passingthrough the cooling chamber. By communicating exhaust air through thecooling chamber there is obtained an efficient cooling of the anglegearing while maintaining favorable outer dimensions of the housing.

In US 20100071926, a circumferential duct is formed partly around theouter ring of a sealed bearing, to enable heat transfer from the bearingto the passing exhaust air; a cooling chamber, a channel and a coolingpassage should be formed in the outer wall which is disposed between thecylinder and the forward angle gear arrangement, and the cooling passageis formed around a ball bearing which is disposed within the outer walland around an output shaft. The formation of the air cooling systemrequires many parts, and many air passages or channels should beadditionally formed in these parts, so that the pneumatic power tool haslots components and a complicated structure which is not easily tofabricate/assemble and has high production cost. Moreover, the aircooling system does not provide an air curtain (air jet) which can blockparticles or dirt out, so that particles or dirt can accumulate on partsand in gap therebetween.

The present invention is, therefore, arisen to obviate or at leastmitigate the above-mentioned disadvantages.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a flow-bypassingstructure of a grinding tool and the grinding tool which includes theflow-bypassing structure which can effectively block particles or dirtout so as to prevent entering of particles or dirt into the grindingtool, accumulation of particles or dirt on parts, unsmooth rotation andeven machine abrasion.

To achieve the above and other objects, the flow-bypassing structure ofa grinding tool of the present invention is adapted for being assembledin a main body of a grinding tool. The main body has an intake passageand an exhaust passage. A cylinder is disposed in the interior of themain body and has an air inlet and an air outlet. The air inlet iscommunicated with the intake passage, and the air outlet is communicatedwith the exhaust passage. An airflow pathway is defined to becommunicated with the interior of the cylinder, the air outlet and theexhaust passage. A rotor is disposed in the cylinder. A rotational axlebase is rotatably disposed through the cylinder and in a rotationalcooperative relationship with the rotor. An end of the rotational axlebase is extended and formed with a rotational working portion which isoperable from an outside of the cylinder. The surroundings of therotational working portion define a space. A flow-bypassing passage iscommunicated with the airflow pathway and the space, and an end of theflow-bypassing passage is open toward the space.

To achieve the above and other objects, the present invention furtherprovides a grinding tool which includes the above-mentionedflow-bypassing structure.

The present invention will become more obvious from the followingdescription when taken in connection with the accompanying drawings,which show, for purpose of illustrations only, the preferredembodiment(s) in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of the presentinvention;

FIG. 2 is a cross-sectional view of the first embodiment of the presentinvention;

FIG. 3 is a partial perspective view of the first embodiment of thepresent invention;

FIG. 4 is a partial breakdown drawing of the first embodiment of thepresent invention;

FIG. 5 is a drawing showing a second embodiment of the presentinvention;

FIG. 6 is a drawing showing a third embodiment of the present invention;

FIG. 7 is a drawing showing a fourth embodiment of the presentinvention;

FIG. 8 is a drawing showing a fifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 to 4 for a first embodiment of the presentinvention. A flow-bypassing structure of a grinding tool of the presentinvention is adapted for being assembled in a main body 1 of a grindingtool. The main body 1 has an intake passage 11 and an exhaust passage12. The intake passage 11 is provided for being communicated with a highpressure gas source and making the high pressure gas enter the main body1. The exhaust passage 12 is provided for venting the used high pressuregas.

A cylinder 2 is disposed in the interior of the main body 1 and has anair inlet 21 and an air outlet 22. The air inlet 21 is communicated withthe intake passage 11, and the air outlet 22 is communicated with theexhaust passage 12. An airflow pathway 23 is defined to be communicatedwith the interior of the cylinder 2, the air outlet 22 and the exhaustpassage 12. A rotor 24 is disposed in the cylinder 2. The high pressuregas goes through the intake passage 11 and enters the interior of thecylinder 2 from the air inlet 21 to drive the rotor 24, and then thehigh pressure gas will be vented out through the air outlet 22 and theexhaust passage 12. In this embodiment, the cylinder 2 includes atubular member 25 and two lid members 26. Two corresponding ends of thetubular member 25 are open ends. The two lid members 26 are respectivelydisposed on the two corresponding ends of the tubular member 25 and havecorrespondingly a first axle hole 261 and a second axle hole262. Morespecifically, a wall of the tubular hole 25 and the two lid members 26are correspondingly formed with through holes and detachably mounted inthe through holes via an elastic latch 27 so as to be mutuallyconnected.

A rotational axle base 3 is rotatably disposed through the cylinder 2and in a rotational cooperative relationship with the rotor 24. Morespecifically, the rotational axle base 3 is rotatably disposed in thefirst axle hole 261 and the second axle hole 262 through at least oneaxle bearing 31. An end of the rotational axle base 3 is extended out ofthe first axle hole 261 and connected with the cylinder 2 through aconnecting member such as a c-ring 32. An end of the rotational axlebase 3 is extended and formed with a rotational working portion 33 whichis operable from an outside of the cylinder 2. The surroundings of therotational working portion 33 define a space 34. A grinding sheet 4 isdetachably mounted on the rotational working portion 33, so the grindingsheet 4 can rotate with the rotational working portion 33 to carry outgrinding operation.

In this embodiment, a lower part of the main body 1 surrounds therotational working portion 33, and the space 34 is formed among thelower part of the main body 1, the cylinder 2 and the rotational workingportion 33. From another viewpoint, the space 34 is locatedcorrespondingly under the cylinder 2 (under a bottom lid of the cylinder2). Preferably, a side of the cylinder 2 facing the space 34 is formedwith an abutting ring 28 (such as a binding ring). The abutting ring 28is surroundingly disposed in the rotational axle base 3, and theabutting ring 28 is abutted against the main body 1 and the cylinder 2so as to fixedly position the cylinder 2 in the main body 1. Preferably,an outer peripheral face of the abutting ring 28 is formed with threads(but not limited thereto) and can be screwed to an inner face of themain body 1 so as to make the cylinder 2 detachably fixed to the mainbody 1.

A flow-bypassing passage 5 is communicated with the airflow pathway 23and the space 34, and an end of the flow-bypassing passage 5 is opentoward the space 34. More specifically, the flow-bypassing passage 5 isdisposed through a side wall of the cylinder 2. The flow-bypassingpassage 5 is disposed on the lid member 26 near the space 34 andsubstantially along an axis of the rotational axle base 3; that is, anopening of the flow-bypassing passage 5 is preferably substantiallytoward the rotational working portion 33, wherein the flow-bypassingpassage 5 goes through a gap between the abutting ring 28 and therotational axle base 3. Understandably, the flow-bypassing passage 5 iscommunicated with the interior of the cylinder 2 and the space 34, orthe flow-bypassing passage 5 can also be communicated with the exhaustpassage 12 (extended from the interior of the main body 1 andcommunicated with a space outside the grinding tool) in the exterior ofthe cylinder 2 and the space 34.

In a second embodiment of the present invention shown in FIG. 5, acylinder 2′ includes a tubular member 25′ and a lid member 26′. An endof the tubular member 25′ near the space is an open end, and the otherend of the tubular member 25′ has a first axle hole 261′. The lid member26′ is disposed on the open end of the tubular member 25′ and has asecond axle hole 262′ corresponding to the first axle hole 261′. Therotational axle base 3 is rotatably disposed in the first axle hole 261′and the second axle hole 262′, wherein the flow-bypassing passage 5 isdisposed at the end of the tubular member 25′ near the space andpreferably substantially along an axis of the rotational axle base 3(substantially toward the rotational working portion 33).

In a third embodiment of the present invention shown in FIG. 6, acylinder 2″ includes a tubular member 25″ and a lid member 26″. An endof the tubular member 25″ remote form the space has a first axle hole261″, and the other end of the tubular member 25″ is an open end. Thelid member 26″ is disposed on the open end of the tubular member 25″andhas a second axle hole 262″ corresponding to the first axle hole 261″.The rotational axle base 3 is rotatably disposed in the first axle hole261″ and the second axle hole 262″, wherein the flow-bypassing passage 5is disposed on the lid member 26″ and preferably substantially along anaxis of the rotational axle base 3 (substantially toward the rotationalworking portion 33).

Furthermore, in a fourth embodiment of the present invention, aflow-bypassing passage 5′ can be disposed through a part of the mainbody 1 (formed in a single part or among assembled parts), and it ispreferable that the flow-bypassing passage 5′ has an opening toward therotational working portion 33 (as shown in FIG. 7). On the other hand,the flow-bypassing passage can be formed between the main body 1 and theside wall of the cylinder (not shown). Any other way will be adaptive aslong as the gas can be guided out into the space.

In a fifth embodiment of the present invention as shown in FIG. 8, aside of an abutting ring 29 facing the cylinder 2 has an outer ringprotrusion 291 and an inner ring recession 292 which is relativelyremote from the cylinder 2, and an end of the flow-bypassing passage isopen toward the inner ring recession. Preferably, a sealing ring member293 is surroundingly disposed between the outer ring protrusion 291 andthe inner ring recession 292. The sealing ring member 293 is air-tightlyabutted against the cylinder 2 and the inner ring recession 292 so as tomake sure that the gas is effectively guided out into the space 34. Theabutting ring 29 is disposed around a end portion of the cylinder 2 soas to form a circular passageway located between the abutting ring 29and the cylinder 2 and communicating with the space 34, and the innerring recession 292 and the end portion of the cylinder 2 form a circularspace communicating with the flow-bypassing passage and the circularpassageway. Whereby, the used high pressure gas out from the cylinder 2first comes into and fills the circular space, and then passes throughand injects from the circular passageway to form a circular gas curtainwith high flow speed around the rotational axle base. With the formationof the high-speed circular gas curtain, particles or dirt can beeffectively blocked so as to prevent entering of particles or dirt intothe grinding tool, accumulation of particles or dirt on parts.

The present invention further provides a grinding tool 100. The grindingtool 100 includes the flow-bypassing structure of a grinding tool shownin the embodiment according to FIG. 1, 2, 3, 4, 5, 6, 7 or 8. In thefirst embodiment shown in FIGS. 1 to 4, the grinding tool includes amain body 1, a cylinder 2, a rotor 24 and a rotational axle base 3. Themain body 1 has an intake passage 11 and an exhaust passage 12. Thecylinder 2 is disposed in the interior of the main body 1 and has an airinlet 21 and an air out let 22. The air inlet 21 is communicated withthe intake passage 11, and the air outlet 22 is communicated with theexhaust passage 12. An airflow pathway 23 is defined to be communicatedwith the interior of the cylinder 2, the air outlet 22 and the exhaustpassage 12. The rotor 24 is disposed in the cylinder 2. The rotationalaxle base is rotatably disposed through the cylinder 2 and in arotational cooperative relationship with the rotor 24. An end of therotational axle base 3 is extended and formed with a rotational workingportion 33 which is operable from the outside of the cylinder 2. Thesurroundings of the rotational working portion 33 define a space 34. Aflow-bypassing passage 5 is communicated with the airflow pathway 23 andthe space 34, and an end of the flow-bypassing passage 5 is open towardthe space 34.

Through the present invention, the flow-bypassing passage is disposedbetween the airflow pathway and the space to guide part of the used highpressure gas out into the space. When the high pressure gas passes theflow-bypassing passage, a jet flow will be created. The particlesproduced during the grinding process can be effectively blocked by thehigh-speed jet flow or circular gas curtain to prevent problems likedirt accumulation, unsmooth rotation and machine abrasion.

In addition, the cylinder can be designed to have “a tubular member andtwo lid members” or “a tubular member and a lid member” and detachablyassembled; therefore, it is convenient to mount, dismount, maintain andreplace the members, and there is no need to replace a whole set when asingle member is broken.

Although particular embodiments of the invention have been described indetail for purposes of illustration, various modifications andenhancements may be made without departing from the spirit and scope ofthe invention. Accordingly, the invention is not to be limited except asby the appended claims.

What is claimed is:
 1. A flow-bypassing structure of a grinding tooladapted for being assembled to a main body of the grinding tool, themain body having an intake passage and an exhaust passage, a cylinderdisposed in an interior of the main body and having an air inlet and anair outlet, the air inlet communicated with the intake passage, the airoutlet communicated with the exhaust passage, an airflow pathway definedto be communicated with the interior of the cylinder, the air outlet andthe exhaust passage, a rotor being disposed in the cylinder, arotational axle base rotatably disposed though the cylinder and in arotational cooperative relationship with the rotor, an end of therotational axle base extended and formed with a rotational workingportion which is operable from an outside of the cylinder, thesurroundings of the rotational working portion defining a space, anabutting ring neighboring the space abutted against the main body andthe cylinder so as to fixedly position the cylinder in the main body, aflow-bypassing passage disposed through a side wall of the cylinder andcommunicated with the airflow pathway, an end of the flow-bypassingpassage being open toward the abutting ring and a venting pathwaydisposed through the abutting ring and communicated with the space andthe flow-bypassing passage.
 2. The flow-bypassing structure of thegrinding tool of claim 1, wherein the cylinder includes a tubular memberand a lid member, an end of the tubular member remote from the space hasa first axle hole, the other end of the tubular member is an open end,the lid member is disposed on the open end of the tubular member and hasa second axle hole corresponding to the first axle hole, and therotational axle base is rotatably disposed in the first and second axleholes.
 3. The flow-bypassing structure of the grinding tool of claim 1,wherein the cylinder includes a tubular member and a lid member, an endof the tubular member near the space is an open end, the other end ofthe tubular member has a first axle hole, the lid member is disposed onthe open end of the tubular member and has a second axle holecorresponding to the first axle hole, and the rotational axle base isrotatably disposed in the first and second axle holes.
 4. Theflow-bypassing structure of the grinding tool of claim 1, wherein thecylinder includes a tubular member and two lid members, the twocorresponding ends of the tubular member are open ends, the two lidmembers are respectively disposed on the two corresponding ends of thetubular member and has corresponding first and second holes, and therotational axle base is rotatably disposed in the first and second axleholes.
 5. The flow-bypassing structure of the grinding tool of claim 2,wherein the flow-bypassing passage is disposed at the end of the tubularmember near the space and substantially along an axis of the rotationalaxle base.
 6. The flow-bypassing structure of the grinding tool of claim3, wherein the flow-bypassing passage is disposed on the lid member andsubstantially along an axis of the rotational axle base.
 7. Theflow-bypassing structure of the grinding tool of claim 4, wherein theflow-bypassing passage is disposed on the lid member near the space andsubstantially along an axis of the rotational axle base.
 8. Theflow-bypassing structure of the grinding tool of claim 1, wherein theflow-bypassing passage is communicated with the interior of the cylinderand the venting pathway.
 9. The flow-bypassing structure of the grindingtool of claim 1, wherein the flow-bypassing passage is communicated withthe exhaust passage on the exterior of the cylinder and the ventingpathway.
 10. The flow-bypassing structure of the grinding tool of claim1, wherein part of the main body surrounds the rotational workingportion, and the space is formed among the part of the main body, thecylinder and the rotational working portion.
 11. The flow-bypassingstructure of the grinding tool of claim 1, wherein the abutting ring andthe cylinder define the venting pathway.
 12. The flow-bypassingstructure of the grinding tool of claim 1, wherein a side of theabutting ring facing the cylinder is formed with an outer ringprotrusion and an inner ring recession which is relatively remote fromthe cylinder, and the end of the flow-bypassing passage is open towardthe inner ring recession.
 13. The flow-bypassing structure of thegrinding tool of claim 12, wherein a sealing ring member is furthersurroundingly disposed between the outer ring protrusion and the innerring recession, and the sealing ring member is air-tightly abuttedagainst the cylinder and the inner ring recession.
 14. A grinding tool,including the flow-bypassing structure of claim 1.